Method for selecting interactive voice response modes using human voice detection analysis

ABSTRACT

In an interactive voice response system, a method is provided for selective enhancement of voice recognition capability during an interaction. The method includes the acts (a) taking a call and prompting for a voice response from the caller, (b) failing to recognize the response, (c) executing a routine to detect and isolate the captured word or phrase in the response, and (d) attempting to recognize the response a second time.

CROSS-REFERENCE TO RELATED APPLICATIONS

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BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is in the field of interactive voice recognition(VR) systems and pertains particularly to methods for using human voicedetection results to select and implement IVR mode during interactionwith a caller.

2. Discussion of the State of the Art

Interactive voice response (IVR) units are used primarily to interfacewith callers accessing a point of service or point of routing in acommunications network environment, typically a telephone environment.Modern IVR systems enable a caller to make specific menu selections bypushing a button on duel tone multi-frequency (DTMF) enabled telephones.Most modern telephones use the DTMF system. More recently, IVR systemshave been improved to include voice recognition capability. Voicerecognition at an IVR unit often is made available in conjunction withstandard DTMF pushbutton selection options.

One reason that voice recognition is used in an IVR system is to enablethose without pushbutton capability on their communications devices tointeract with the system. This is suitable in a low noise environmentwhere the user's voice is very clear. State-of-art systems are notalways accurate in voice interpretation even in lower noiseenvironments. In moderate and high noise environments like transitstations, airports, clubs, automobiles, or the like, the IVR often failsto recognize the human voice because of interference of the backgroundnoises and therefore is unable to recognize the speech pattern underthose adverse conditions. User's that do not have buttons on theirdevices cannot successfully prosecute the transaction under thosecircumstances. Duel mode (voice and DTMF) IVR routines attempt torecognize the human voice by default, but will accept a tone for menuselection. The menu typically prompts a user to say a particular word orphrase, or to enter an equivalent value by depressing a key on thecommunications device. A user operating in a moderate to high noiseenvironment often attempts to enunciate the voice key first for everyprompt response before finally depressing the appropriate value key notunderstanding that the system will not recognize any of the user's voiceenunciations because of the background noise level and/or type.

Human voice detection solutions do exist for the purpose of detectinghuman voice in an audio signal which may include background noise. Onemethod for detecting human voice in an audio signal is described in U.S.Pat. No. 6,321,194 issued Nov. 20, 2001 to Brooktrout Technology, Inc.titled Voice Detection in Audio Signals. The method uses fuzzy logic todetermine a likelihood of human voice in a random audio signal sample byobserving power thresholds and frequencies in the sample and generatingresult values that are compared against known human voice frequencies.The algorithm determines a statistical likelihood of whether the humanvoice is detected in the sample. Likewise, ways of isolating human voicefrom background noise in an audio sample have been researched anddeveloped that employ other digital and analog methods to detect and todifferentiate human voice from random noise.

What is clearly needed in the art is a method for selecting andimplementing a default IVR mode based on HVD analysis of the voiceresponses received during interaction. A system such as this wouldstreamline IVR interaction for callers enabling faster call handling.

SUMMARY OF THE INVENTION

In an interactive voice response system, a method is provided forenhancing voice recognition capability during an interaction. The methodincludes (a) taking a call and prompting for a voice response from thecaller, (b) attempting to recognize the response, (c) upon failing torecognize the response in step (b), executing a routine to detect andisolate the captured word or phrase in the response, and (d) attemptingto recognize the response a second time. In one aspect, in step (a), thecall is from one of a cell phone, a PSTN-connected telephone, or a voiceenabled headset. In step (b), failure is due to high non-human noiselevels in the response.

In a preferred aspect, in step (c), the routine is a human voicedetection routine aided by human voice detection software. Also in thisaspect, the noise that is not part of the word or phrase of the responseis subtracted out of the captured data. In one aspect in step (d), thesecond attempt uses the same voice recognition routine as the firstattempt.

According to another aspect of the present invention, in an interactivevoice response system, a method is provided for automatically switchingmode of the system during an interaction based on performance of thesystem. The method includes the acts (a) taking a call and prompting fora voice response from the caller, (b) attempting to recognize theresponse, (c) upon failing to recognize the response in step (b),executing a routine to detect and isolate the captured word or phrase inthe response, (d) failing to recognize the response a second time, and(e) overriding voice detection mode and setting pushbutton mode asdefault mode for the rest of the current transaction.

In one aspect of the method, in step (a), the call is from one of a cellphone, a PSTN-connected telephone, or a voice enabled headset. In step(b), failure is due to high non-human noise levels in the response. In apreferred aspect, in step (c), the routine is a human voice detectionroutine aided by human voice detection software. In one aspect, in step(d), there is not enough of the human voice detected to facilitate amatch in the second recognition attempt. In one aspect, in step (e), thecaller is prompted to notify of the override condition.

In one aspect of the method, whether or not there is a step (e) for modeoverride, step (a) is replaced by a step (a) for placing a call and uponthe call being answered, prompting the called party for a response.

According to another aspect of the present invention, a duel mode IVRsystem is provided. The system includes a telephone interface switch, avoice recognition software instance and library, and a human voicedetection software instance. The human voice detection software iscalled and executed during an IVR interaction with a caller only if thevoice recognition software routine fails to recognize a response utteredby the caller.

In one embodiment, the telephone switch is a central office switchconnected to a private branch exchange (PBX). In one embodiment, thevoice recognition software is Voice over Extensible Markup Language(VoXML) enabled.

In yet another aspect of the invention, a machine readable medium isprovided, the medium having thereon a set of instructions that cause amachine to perform a method including (a) taking a call and promptingfor a voice response from the caller, (b) attempting to recognize theresponse, (c) upon failing to recognize the response in step (b),executing a routine to detect and isolate the captured word or phrase inthe response.

In one aspect in step (a), the call is taken at an interactive voiceresponse system. In one aspect, in step (c), the routine includes a substep for setting the default mode of the interactive voice responsesystem for the rest of the interaction with the caller according to theresult of a second attempt to recognize the response.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIG. 1 is an architectural overview of an IVR system enhanced with humanvoice detection according to an embodiment of the present invention.

FIG. 2 is a process flow chart illustrating acts for selecting andimplementing IVR mode during interaction according to an embodiment ofthe present invention.

DETAILED DESCRIPTION

FIG. 1 is an architectural overview of a voice telephony environment 100including an IVR system enhanced with human voice detection according toan embodiment of the present invention. Voice telephony environment 100includes a public switched telephone network (PSTN) 102, a cellularnetwork 101, and a communication center service point 103.

PSTN network 102 may instead be a private telephone network instead of apublic network. PSTN network 102 includes a private branch exchange(PBX) telephony switch 107. Switch 107 may be an automated calldistributor (ACD) type switch, or some other telephony network switchcapable of processing and routing telephone calls. PBX 107 is connectedto a central office switch (COS) 110 located within communication centerservice point 103 by a telephone trunk 109. Service point 103 alsoincludes an interactive voice response (IVR) unit 111, connected to COS110 via a computer telephony integration (CTI) link.

Cellular network 101 may be any type of digital or analog networksupporting wireless telephony without departing from the spirit andscope of the present invention. Network 101 includes a cell tower 104connected by a telephone trunk to an edge router 106 just inside thePSTN 106. In this example, callers 105 (a-n) communicate through tower104, which routes the call into the PSTN via trunk 110 through router106 on to PBX 107. Callers 108 (a-n) are wired to PBX 107 via telephonewiring. QOS may at times be quite different for the different networks101 and 102 in terms of voice quality and the amount of noiseinterference. Generally speaking, a wired telephone on a dedicatedconnection has better voice quality more of the time than, for example,a cellular telephone over a shared connection. Moreover, other factorsmay contribute to noise that is captured from the caller environment andcarried along with the voice during a call.

IVR 111 intercepts calls from callers 108 (a-n) and from callers 105(a-n) and attempts to provide service to those callers based on plannedvoice interaction (voice application) sessions with those callers. Thevoice interactions may be any type of voice interaction from those thatprovide internal routing to a live agent, and/or those that actuallycomplete the call using automated transaction processing techniques.

In this example, IVR 111 has a voice over XML voice recognition program113 provided that utilizes a database 112 that contains a programmablelibrary of word and phrases to aid in recognizing voice commands, wordsand/or phrases spoken by the caller. The spoken voice is recognized bysearching for the VoXML equivalent stored in the database. It isimportant to note herein that voice does not have to be recognizedperfectly for a successful match of a caller's spoken word or phrase indatabase 112. If a phrase is mostly recognized, then the software maystill produce the correct system response to the voice phrase uttered bythe caller. There are several known ways including statistical patternmatching that can be used to help the voice recognition accuracy withinthe digital processing realm of IVR 111. Another technique is to poolvariant response words or variances of response phrases and equate themto a same value.

In this example, IVR 111 has, in addition to standard voice recognitioncapability, an instance of human voice detection (HVD) software providedthereto and executable thereon. HVD 114 is provided to enhance the voicerecognition capability of IVR 111 by detecting in the audio capturedfrom the caller the human voice portion of the total audio data.Provided that the human voice data can be reliably detected then thedata that does not appear to be human voice can be subtracted from anequation before standard voice recognition is employed. The method canbe applied after voice recognition has failed to recognize an utteredword or phrase on a first attempt. Attempting to recognize the callerword or phrase using standard non-enhanced voice recognition softwaremay be a default routine because under low noise circumstances there maybe no need for enhancement. However under moderate to high noisescenarios, for example, a cell phone caller in a construction zone, HVDmay be helpful in isolating the human portion of the signal forpresentation of only the human signal to the voice recognition software.

In actual practice, if caller 108 a, for example, is in interaction withIVR 111 at switch 110, standard voice recognition software may work finefor most of the prompt/response rounds. However, if during one round,the caller's word or phrase is not immediately recognized by thesoftware, then instead of forcing the caller to depress a button, HVDcan be used to refine the signal and a second attempt to recognize theword or phrase may be initiated. The time it takes to call the HVDroutine and execute it to completion is negligible in terms of callflow. COS 110 has a processor of suitable power and speed to run ananalysis very quickly. In another instance, a cellular caller 105 n mayrequire HVD intervention for each prompt/response round at IVR 111because of background noise prevalence. However, the noise causing theproblem might be temporary. Therefore, attempting to recognize thecaller's word or phrase using the standard VRT may allow discontinuanceof the HVD cycle for one or more prompt/response rounds.

It will be apparent to one with skill in the art that the method of thepresent invention can be used to improve the interaction accuracy.Likewise, there would be less dependence on the backup DTMF pushbuttonmethod for the caller to insert a value. Therefore, those callers thatdo not have pushbutton capability on their communications devices wouldreceive better service. If the system is implemented according to themethod described, the voice application prompts would not necessarily berequired to include a push button value along with the appropriate voiceresponse word or phrase. If the enhanced system failed to recognize thecaller's word or phrase one or a specified number of times, a systemprompt might be rotated in that informs the caller that voicerecognition has been turned off because of the noise level or type thesystem is experiencing. In this case, the subsequent prompts could bebased on DTMF pushbutton only and VRT capability could be suspended forthe rest of that session.

One with skill in the art will recognize that the method described canbe implemented in a telephony environment or in a voice over internetprotocol environment where an IVR equivalent is implemented. The IVRsystem itself may be caused to switch between modes in midstream basedon the application of the method integrated with controlling IVRsoftware. The HVD routine may be plugged into normal IVR programming byinserting a removable media containing the sequence start all of thetasks and the sequence end. The routine can be inserted into any of thevoice application running on the system.

FIG. 2 is a process flow chart illustrating acts 200 for selecting andimplementing IVR mode during interaction according to an embodiment ofthe present invention. The following acts reflect just one of a numberof possible processes that could be programmed into IVR control softwareand caused to run automatically as calls are processed by the IVRsystem.

In step 201, the IVR boots or otherwise is brought online. In step 202,DTMF pushbutton recognition is activated as a backup measure. In step203, voice recognition is activated and set as the default mode. It isnoted herein that pushbutton recognition can be active transparently tocallers where IVR prompts do not inform callers of pushbutton valuesequivalent to voice words or phrases required to navigate the system.

At step 204, the IVR system is ready to accept calls from callers. Atstep 205, an incoming call is accepted. At step 206, the IVR systemplays the greeting and menu options to the caller and waits for thecaller voice response. At step 207, the IVR system receives a voiceresponse from the caller according to the menu options.

At step 208, the IVR system attempts to recognize the caller's responseusing the standard VRT software. If at step 208, the caller's responseis effectively recognized, then the IVR system determines if thetransaction is complete in step 209. If the transaction is complete atstep 209, then at step 210 the process ends and the system takes thenext call waiting. If at step 209, the transaction is not yet complete,then the process loops back to step 206 where the IVR system plays thenext prompt to the caller and waits for the caller's next response. Theprocess then moves to step 208 again where the IVR determines if therecognition was successful using the standard VRT technology. If so,then the loop continues without calling any additional routines untilthe caller's response is not recognized using standard recognitionsoftware at step 208.

At step 208, any time during the interaction with the caller, if theresponse is not recognized using standard VRT, then at step 214, the HVDsoftware routine analogous to SW 111 of FIG. 1 is activated. The processthen moves to step 211 where the HVD routine analyses the recordedresponse signal, to detect the human voice in the signal. At step 212,the system determines if the human voice is detected and can be isolatedfrom other noise in the signal. If at step 212, the human voice isidentified and isolated from the rest of the signal, then at step 213,the HVD routine subtracts the noise patterns from the signal. It isnoted herein that the HVD process may be performed on a suitable digitalsignal processor that has all of the required circuitry and power forperforming the required calculations to detect the human voice patternand to isolate it from the noise patterns.

The process then moves back to step 208 where the IVR system againattempts to recognize the caller's word or phrase from a cleaner signal.If at step 208, the system still cannot recognize the caller's word orphrase after enhancement, then the process may resolve to step 215 wherethe system turns off VRT and may prompt the caller with a notice orinstruction to use DTMF pushbutton interaction for the rest of the call.In this act, the IVR may play a voice message that tells the caller thatdue to high interference or background noise, please depress the keys onyour communications device when prompted to do so to navigate the restof this transaction. It is noted herein that the system may revert toabandoning VRT for any caller just after one failure of the system torecognize the caller's word or phrase after HVD analysis.

If at step 208 the system does recognize the caller's utterance afterHVD intervention, and in step 209, it is not the end of the transaction,then the process loops back to step 206 and continues with step 207 and208 using standard VRT. In this example, HVD is not used unless there isa failure with the standard approach. In a case where the caller doesnot have touch tone buttons or is not able to interact with them becausethe caller is otherwise engaged in driving or some other focusedactivity, then the system may simply ask the caller to try again later.At step 212, if HV is not detected by the HVD system, then by defaultstep 215 may occur, switching IVR mode to pushbutton for the rest of thetransaction.

It will be apparent to one with skill in the art that some variation maybe afforded to this process of acts 200 without departing from thespirit and scope of the present invention. In one embodiment, caller'swho may also subscribe to a service using the method of the inventionmay set their own preference for DTMF pushbutton or VRT interaction bydefault. Such allowances could change the process acts in terms ofnumber of acts and order of acts. Other acts may be inserted, forexample, to convert language. In this way, a Spanish speaker mayinteract with the system and have system output delivered in Spanish. Itwill also be apparent to the skilled artisan that the method of thepresent invention may also be practiced during an IVR assisted outboundcalling campaign. There are many possibilities.

The method of the present invention may be practiced within theenvironment of an IVR system or in conjunction with any othercomputerized voice enabled interaction point. It will be understood bythe skilled artisan that the invention may be practiced using some of, acombination of, or all of the components and acts described herein. Inlight of the embodiments described, the invention should be afforded thebroadest possible interpretation under examination. The spirit and scopeof the present invention should be limited only by the following claims.

1. In an interactive voice response system, a method for enhancing voicerecognition capability during an interaction comprising the steps of:(a) taking a call and prompting for a voice response from the caller;(b) attempting to recognize the response; (c) upon failing to recognizethe response in step (b), executing a routine to detect and isolate thecaptured word or phrase in the response; and (d) attempting to recognizethe response a second time.
 2. The method of claim 1, wherein in step(a), the call is from one of a cell phone, a PSTN-connected telephone,or a voice enabled headset.
 3. The method of claim 1, wherein in step(b), failure is due to high non-human noise levels in the response. 4.The method of claim 1, wherein in step (c), the routine is a human voicedetection routine aided by human voice detection software.
 5. The methodof claim 1, wherein in step (c), the noise that is not part of the wordor phrase of the response is subtracted out of the captured data.
 6. Themethod of claim 1, wherein in step (d), the second attempt uses the samevoice recognition routine as the first attempt.
 7. In an interactivevoice response system, a method for automatically switching mode of thesystem during an interaction based on performance of the systemcomprising the steps of: (a) taking a call and prompting for a voiceresponse from the caller; (b) attempting to recognize the response; (c)upon failing to recognize the response instep (b), executing a routineto detect and isolate the captured word or phrase in the response; (d)failing to recognize the response a second time; and (e) overridingvoice detection mode and setting pushbutton mode as default mode for therest of the current transaction.
 8. The method of claim 7, wherein instep (a), the call is from one of a cell phone, a PSTN-connectedtelephone, or a voice enabled headset.
 9. The method of claim 7, whereinin step (b), failure is due to high non-human noise levels in theresponse.
 10. The method of claim 7, wherein in step (c), the routine isa human voice detection routine aided by human voice detection software.11. The method of claim 7, wherein in step (d), there is not enough ofthe human voice detected to facilitate a match in the second recognitionattempt.
 12. The method of claim 1, wherein in step (e), the caller isprompted to notify of the override condition.
 13. The method of claim 1,wherein step (a) is replaced by a step (a) for placing a call and uponthe call being answered, prompting the called party for a response. 14.A duel mode IVR system comprising: a telephone interface switch; a voicerecognition software instance and library; and a human voice detectionsoftware instance; characterized in that the human voice detectionsoftware is called and executed during an IVR interaction with a calleronly if the voice recognition software routine fails to recognize aresponse uttered by the caller.
 15. The system of claim 14, wherein thetelephone switch is a central office switch connected to a privatebranch exchange (PBX).
 16. The system of claim 14, wherein the voicerecognition software is Voice over Extensible Markup Language (VoXML)enabled. 17.-19. (canceled)